Nicholas I.
Nicholas I designates the following persons:
- Nicholas I (Pope) (820–867), Pope
- Nicholas I (Patriarch) (852–925), Patriarch of Constantinople
- Nikolaus I (Mecklenburg) (before 1164–1200), Prince of Mecklenburg
- Nikolaus I. (Werle) (~ 1210–1277), Lord of Rostock and Lord of Werle
- Nikolaus I (Troppau) (~ 1255–1318), founder of the Premyslid ducal line of Troppau
- Nikolaus I von Gleißenberg († after 1444) abbot of the Benedictine monastery Münsterschwarzach
- Nicholas I (Opole) (~ 1420–1476), Duke of Opole
- Nicholas I (Lorraine) (1448–1473), Duke of Lorraine
- Nicholas I (Russia) (1796–1855), Tsar of Russia and King of Poland
See also:
- Nikola (Montenegro) ( Nikola I, Nicholas I ; 1841–1921), Prince and King of Montenegro
